1. Field of the Invention
The present invention is directed to patient monitoring systems.
2. Discussion of the Related Art
A variety of devices currently are used to monitor physiological conditions of patients. For example, bedside monitors, transport monitors and telemetry transmitters are used for this purpose. Data from these devices generally is transferred in "real-time" to a centrally located station, such as a nurse station in a hospital or other medical treatment facility. Electronic equipment at the central station typically processes and displays this data to persons at the central station. In processing the data, the central station commonly uses electronic equipment to analyze the data to identify anomalies in physiological conditions of the patients being monitored. If such an anomaly is identified, then the central station generates an alarm. This alarm may be annunciated at the central station, may be transmitted to a hallway display (described below), or may be transmitted to a device in the possession of one or more clinicians responsible for the patient whose physiological data triggered the alarm.
The electronic equipment at the central station may falsely identify anomalies in the physiological conditions of patients based upon the data received from patient monitoring devices. For example, normal electrocardiograph (ECG) data may cause a central station to generate false alarms. Because some central stations receive data from a very large number of patients (e.g., in large hospitals), it is not uncommon for many false alarms to be generated by a central station over the course of a day.
In many cases, the only way to determine whether the electronic equipment at the central station has properly identified an anomaly in the physiological condition of a patient is for a clinician to examine a displayed version of the data, for example, an ECG activity display. Only after the clinician has reviewed this display can he or she determine with any degree of confidence whether the alarm generated by the central station is valid or invalid.
In some hospitals, a person at the central station determines whether each alarm generated by the central station electronic equipment is valid or invalid. If this person determines an alarm is valid, then he or she notifies the appropriate nurse or physician that one of his or her patients is having difficulty, or notifies others if some other action is required. The person located at the central station therefore must be medically trained. This medically trained person, however, spends none of his or her time actually caring for patients. Maintaining medically trained personnel at a central station for the sole purpose of reviewing patient alarms can impose a significant financial burden on a medical treatment facility.
In other hospitals, due to increasing pressures to minimize costs, it is not always possible to keep a clinician at the central station at all times. Rather, in these hospitals, clinicians are responsible for care giving in addition to recognizing and responding to patient alarms. Therefore, these clinicians become aware of alarms only when they are in the vicinity of the central station. This can cause delays in the acknowledgment of alarms and therefore can cause delays in the treatment of patients with serious conditions.
Additionally, since the central station monitors several patients concurrently, it can alarm quite frequently. These alarms are annunciated loudly, so that they will be noticed promptly by clinicians at or near the central station. As a result, there is a considerable amount of noise in the central station area. This noise can make it difficult to get someone's attention in this area to let them know something is wrong and may be annoying and distracting to persons in the area.
Instead of maintaining clinically trained personnel at the central station at all times, alarm signals generated by the electronic equipment at the central station may be distributed to one or more clinicians responsible for the patient whose data triggered the alarm, and that clinician then may walk to the central station or the patient's bedside (if bedside monitoring is provided) to view a display of the patient's physiological data. One device used to distribute alarm information to clinicians is a so-called "nurse pager." Generally, a nurse pager alerts a clinician that an alarm has activated for a specific patient by providing an alarm indication, such as an audio or vibrational indication, and provides the clinician with textual information regarding the nature of the alarm.
Nurse pagers, however, do not provide real-time waveforms for the clinician to review, so the clinician must walk to the central station or the patient's room in order to accurately determine the validity or invalidity of the alarm. Therefore, in using this alternative, much of the clinician's time and energy is wasted in walking to the central station or the patient's room in order to validate or invalidate alarms. Further, conventional nurse pagers do not provide a bi-directional link between the "pager" and the "pagee," so that the central station is uncertain at any given time whether a clinician has received an alarm and/or whether the clinician has responded to it.
One device used to review physiological data at a patient's bedside is described in U.S. Pat. No. 5,417,222 to Dempsey et al., which is assigned to the assignee of the present application. This device is portable and interfaces with a telemetry unit at a patient's bedside to allow a clinician to view real-time waveforms representative of the physiological condition(s) of the patient. This device, however, does not provide the ability to receive alarm-related information from the central station and does not permit a clinician to validate or invalidate an alarm received by another device, e.g., a pager. Therefore, if a clinician receives an alarm indication from another device, such as a pager, and uses the Dempsey et al. device to view a patient's physiological data to determine the validity of the alarm (after interfacing with a telemetry transmitter at the patient's bedside), then the clinician generally still must walk to or call the central station in order to validate or invalidate the alarm. This can be inconvenient for the clinician and can consume a large amount of the clinician's time.
As a partial solution to this problem, so-called "hallway displays" are used in some medical treatment facilities. Hallway displays are monitors, mounted in a hallway, that can display real-time physiological data and waveforms to physicians. Some hallway displays also provide for two-way communications between the hallway display and the central station, so that a clinician may acknowledge the receipt of an alarm and/or validate or invalidate an alarm from the hallway display. These displays, however, are relatively large and are fixed permanently to the wall or ceiling, so that clinicians still must walk to specific locations in a treatment facility to view the information they need.
Portable devices that display so-called waveform "snippets" also are known. A waveform snippet essentially is a "snapshot" of a waveform that may be analyzed by a clinician to identify characteristics in the waveform that are indicative of certain medical conditions. These devices, however, do not display real-time waveforms to a user, and do not provide for any communications from the user to a central station. Therefore, they do not: (1) allow a user to acknowledge that he or she has received an alarm for a particular patient, or (2) allow a user to validate or invalidate alarms for a patient whose data is being displayed by the device.
U.S. Pat. No. 5,534,851 to Russek describes a system for paging alarms to specific clinicians, together with some textual information about a particular patient. The Russek handheld device, however, does not display real-time waveforms representing a patient's physiological condition(s) to its user. A clinician using this device therefore cannot, in many situations, accurately validate or invalidate alarms using this device.
What is needed, therefore, is an improved device and method for monitoring the physiological conditions of patients.